Process for beneficiating ores



United States Patent "ice 3,113,922 PRQCEfiS FUR BENEFICHATING GEES Dewey J. Hall, .lr., Bakers-ville, N.., assignor to Enternational Minerals & Chemical Qorporation, a corpu ration of New Yuri: No Drawing. Filed July 25, 1961, Ser. No. 126,516 Claims. ill. 209-166) The present invention generally relates to a process for the beneficiation of ores and mineral concentrates. In a particular aspect this invention relates to the beneficiation of feldspathic rock materials and minerals. In a still more particular aspect it relates to a process for the preparation of potash spar concentrates and soda spar concentrates from mixtures of potash spar and soda spar. In a specific aspect the present invention relates to the separate recovery of a potash spar concentrate and a soda spar concentrate from a flotation concentrate obtained in a froth flotation process for the recovery of feldspar, which flotation concentrate contains potash spar and soda spar.

Feldspar is the name of a group of minerals, specifically aluminosilicates of potassium, sodium, calcium, and occasionally barium. The aluminosilicate of potassium or potash spar and the aluminosilicate of sodium or soda spar are commercially important. They are used as ceramic fluxing agents, a source of alkalies and alumina, and as an ingredient in glass manufacture.

Feldspar ores do not generally contain commercial quantities of a specific pure feldspar mineral. The best potash spar ores usually contain soda spar and, similarly, the best soda spar ores usually contain potash spar. For some uses of feldspar, a particularly high ratio of potash spar to soda spar is desirable and for other uses of feldspar a particularly high ratio of soda spar to potash spar is desirable. For example, for electrical and dental porcelain uses, a high potash spar is needed.

Feldspar ores have for many years been beneflciated by milling methods utilizing magnetic separators. Froth flotation and/ or table concentration to elfect separation of feldspar from quartz and other associated gangue minerals are also now used on a commercial scale.

While flotation operations have been successful in separating feldspars from gangue materials, flotation has not, heretofore, been successfully employed to separate chemically different feldspars; e.g., potash spar from soda spar, and the like. The present invention is directed to the problem of effecting separation of potash spar from soda spar.

Accordingly, it is an object of the present invention to provide a process for the beneflciation of mixtures of minerals comprising potash spar and soda spar.

It is another object of the present invention to provide a process for the beneficiation of feldspar flotation concentrates containing potash spar and soda spar.

It is a further object of the present invention to provide a process for the beneficiation of feldspathic ores containing potash spar and soda spar.

It is an additional obiect of the present invention to provide a process for preparing a relatively high potash spar content concentrate.

It is a still further object of the present invention to provide a process for preparing a relatively high soda spar content concentrate.

It is a specific object of the present invention to effect a substantial separation of potash spar from soda spar in a flotation operation.

These and other objects and advantages of the invention will be apparent to those skilled in the art from the description of the invention.

Generally described, the present invention comprises 3,113,922 Patented Dec. 10, 1963 n as subjecting a mixture of minerals comprising potash spar and soda spar to flotation in the presence of a cationic collector and a sodium compound selected from the group consisting of sodiumnietasilicate, sodium chloride, and mixtures thereof.

The mixture of minerals comprising potash spar and soda spar may be any mixture of the two in which these materials are substantially liberated from each other and includes, inter alia, feldspar ores, feldspar flotation con centrates, feldspar electorstatic concentrates, tabling concentrates, etc. The mixture preferably contains discrete particles high in potash spar content and discrete particles high in soda spar content.

In accordance with the present invention, separation of the potash spar from the soda spar and other gangue constituents is accomplished by conditioning the feed first with a depressant for the soda spar and then with a flotation reagent comprising a cationic collector, and subjecting the conditioned feed to froth flotation.

When the feed is a natural ore it is usually comminuted to effect a substantial degree of liberation of the potash spar from the soda spar and from the gangue and to effect reduction to a size where the material is amenable to beneiiciation by froth flotation. Generally, the particles should be smaller than 4 mesh. The most satisfactory particle size range for feldspar beneficiation, from an economic standpoint, is Where approximately all of the particles are of a size between about 8 mesh and about 200 mesh, most of the particles preferably being between about 20 mesh and about mesh. When the feed to the process of this invention is a concentrate recovered from a beneflciation process, the mixture will generally be of a particle size suitable for beneficiation in accordance with the present invention.

The liberated feed is mixed with Water to form an aqueous pulp or slurry and conditioned with a cationic type collector and a soda spar depressant. This conditioning step is generally carried out at high solids content although it may be done at flotation density if de sired.

The cationic collector ispreferably of the amine type. Such cationic collectors as are conventionally used in the cationic flotation of feldspar minerals are contemplated for use in the present invention. Preferred aminetype reagents are long chain aliphatic amines containing at least one alkyl group having 12 to 20 carbon atoms, their addition salts, and derivatives thereof, such as the amine acetate, and amine hydrochlorides. Specific examples of these cationic reagents are cocoa amine, soya amine, cocoa diamine, tallow diamine and the like. The cationic collector is used in an effective amount which may vary over fairly wide limits, but generally between about 0.01 lb. and 2.5 lbs. of such reagent per ton of solids being treated.

Frothing agents, extenders, and other agents such as pine oil, kerosene, fuel, etc., are optionally but generally present during flotation. The amount of these materials may also vary over fairly wide lirnits, and generally are employed in amounts of between about 0.01 lb. and about 5 lbs. per ton of solids in the flotation pulp.

When the flotation feed is an ore containing appreciable amounts of mica and silica, the flotation reagent is usually modified by the addition of fluosil-icic acid and/ or hydrofluoric acid and/or other mineral acids. The pH of the aqueous pulp during the flotation operation on such a feed is preferably within the range of from about 2.0 to about 6.0, and the acid is added in amount to obtain a pH within this range. When the feed to the flotation operation in accordance with the present invention is a feldspar concentrate recovered in a prior flotation operation, it is preferable that no acid be added, that is the flotation op- 3 oration in such a case is preferably in the absence of an acid.

The above materials are generally present during a con ventional feldspar flotation operation; however, as hereinhefore set forth, when the flotation is conducted in the presence of a sodium compound selected from the group consisting of sodium rnetasilicate, sodium chloride, and mixtures thereof, the potassium feldspars may be substantially separated from the sodium feldspars. In other Words, the K O/Na O ratio of a feldspar flotation concentrate recovered in a flotation operation conducted in the presence of a sodium compound selected from this group is higher than .when the flotation is conducted in the absence of such a sodium compound. Other sodium compounds have been tested but they have been generally unsuccessful, indicating the high specificity of the sodium chloride and sodium metasilicate of this invention.

In accordance with the present invention, the mixture of potash feldspar and soda feldspar is conditioned with the sodium compound before conditioning with the cationis collector. The sodium compound depresses the flotation of the soda spar and is generally denominated a depressant.

The sodium compound is used in an effective amount, generally within the range of from about 0.1 to about 50 lbs. and preferably within the range of from about 0.5 to about 25 lbs. of sodium compound per ton of solids in the aqueous pulp.

It is necessary that the sodium depressant be added to the solids mixture of potash spar and soda spar before adding the cationic collector. That is, it is necessary to first condition the solids mixture With the sodium depressant and to subsequently add the cationic collector. The other materials such as the extender and the frother, when an extender and frother are used, are also added after the sodium depressant. When an acid is used, the acid is preferably added after the sodium depressant but may be added to the aqueous pulp at any suitable time since its order of addition has not been determined to be critical.

When the conditioning of the solids mixture is effected in an aqueous pulp at flotation density, the pulp may be directly subjected to a froth flotation operation. However, when the conditioning is effected at a relatively high solids content the pulp is preferably diluted tothe proper froth flotation density and then subjected to froth flotation. Such expedients are well known in the froth flotation art. The flotation operation may, of course, be conducted in any suitable type of flotation machine.

The cationic collector has a selective aifinity for the feldspar minerals and, accordingly, tends to float the feldspar minerals during the flotation operation. The sodium compound, however, is a selective suppressor which effectively suppresses the flotation of the soda spar when used in accordance with the present invention. Accordingly, the froth flotation operation in accordance with the present invention achieves a substantial separation of potash spar from soda spar with a resultant higher K O/Na O ratio in the float product overflow from the flotation cell compared to the ratio in the feed. The float product is, therefore, a relatively high potash spar content concentrate. The underflow from the flotation cell will have a substantially lower K O/Na O ratio compared to the overflow or compared to the feed. The underflo-w has a higher Na O/K O ratio than the feed and is, therefore, a relatively high soda spar content concentrate.

In order to give a fuller understanding of the invention, but with no intention to be limited thereto, the following specific examples are given.

Example I A feldspar flotation concentrate recovered in a feldspar flotation operation had the following analysis:

Si0 65.2 A1203 20.4 P6203 0.19 CaO 1.9

Na O 5.8 x 0 6.1

The feldspar flotation concentrate was slurried with water to about 1520% solids and conditioned with the following reagents in the order and in the amounts indicated:

3.5 lbs. of sodium metasilicate (Na SiO per ton of the feldspar flotation concentrate.

0.15 lb. of pine oil per ton of the feldspar flotation concentrate.

0.5 lb. of amine acetate per ton of the feldspar flotation concentrate.

0.2 lb. of kerosene per ton of the feldspar flotation concentrate.

After all of the reagents were added and conditioned for approximately '1 minute, flotation was effected in a Denver type sub A flotation cell. The first or rougher float had the following composition:

Rougher Goncen- Rougher Tailing trate 26% by weight 74% by weight The rougher concentrate was then passed to the first cleaner flotation cell. No additional reagent was added. Fresh water was added to keep the slurry in the flotation cell at about 1520% solids. The composition of the product from the first cleaner cell was as follows:

First Cleaner First Cleaner Concentrate 86.7% Tailing 13.3%

by Wt. by Wt.

The first cleaner concentrate was then passed to the second cleaner flotation cell. No reagents were added. Fresh water was added to the cell to keep the percent solids at about 1520%. The product from the second cleaner cell was by weight of the feed and had the following composition SiO 64.1 A1 0 20.0 F3203 CaO 0.9 Na O 2.7 K 0 10.3

Example II A feldspar flotation concentrate recovered in a feldspar flotation operation had the following chemical and screen analysis:

The feldspar flotation concentrate was slurried with water to about 15-20% solids and conditioned with the following reagents in the order and in the amounts indicated:

25 lbs. of sodium chloride per ton of the feldspar flotation concentrate.

1.0 lb. of rosin amine acetate per ton of the feldspar flotation concentrate.

0.03 lb. of rosin amine residue per ton of the feldspar flotation concentrate.

.10 lb. of carbinol per ton of the feldspar flotation concentrate.

.10 lb. of fuel oil per ton of the feldspar flotation concentrate.

Flotation was effected in a Denver type sub A flotation cell. The first or rougher float had the following composition:

Rougher Conccn- Rougher Tailing trate 20% by wt. 80% by Wt.

O. 20 0. l0 1. 2 l. 9 3. 7 5. 6 9. l 6. 4

The rougher concentrate was then passed to the first cleaner flotation cell. No additional reagent was added. Fresh water was added to keep the slurry in the flotation cell at about -20% solids. The composition of the flotation product from the first cleaner cell was as follows:

First Cleaner First Cleaner Concentrate About Tailing About 80% by wt. by Wt.

Example III In this test the feed was a serni-granular 20 mesh material. Mica had been partially removed. The feldspar content was approximately 65% and the quartz content was approximately This material was slurried with water to about 15% solids and conditioned with the following reagents in the order and in the amounts indicated:

5.0 lbs. of hydrochloric acid per ton of solids in the feed.

15 lbs. of sodium chloride per ton of solids in the feed.

3 lbs. of hydrofluoric acid per ton of solids in the feed.

0.125 lb. of fuel oil per ton of solids in the feed.

3 lbs. of fatty amine hydrochloride per ton of solids in the feed.

After all of the reagents were added the slurry was subjected to flotation in a Denver type sub A flotation cell. The first or rougher float was 25.5% by Weight of the feed and had the following composition:

sio 65.2 A1203 Fe O 0.08 CaO 1.4

The rougher concentrate was then passed to the first cleaner flotation cell. No additional reagent was added. Fresh water was added to keep the slurry in the flotation cell at about 1520% solids. The composition of the product from the first cleaner cell was as follows:

First Cleaner First Cleaner Concentrate Tailing 14% by wt. 86.0% by wt.

This example again illustrates that an effective separation of potash spar from soda spar was achieved. The rougher concentrate had a K /Na O ratio of only 8.2/5.0 or 1.6 while the cleaner concnetrate had :a K O/Na O ratio of 9.7/4.5 or 2.2.

The tailing from the cleaner float had a high soda spar content with the Na O/K O ratio being 5.7/6.0 or 0.95 while the rougher cell concentrate had a Na O/K O ratio of only 5.0/8.2 or 0.6.

The description of the invention utilized specific reference to certain process details; however, it is to be understood that such details are illustrative only and not by way of limitation. Other modifications and equivalents of the invention will be apparent to those skilled in the art from the foregoing description.

Having now fully described and illustrated the invention, what is desired to be secured and claimed by Letters Patent is set forth in the appended claims.

I claim:

1. A process for separating potash spar from soda spar which comprises conditioning a substantially liberated mixture of minerals containing potash spar and soda spar first with a sodium compound selected from the group consisting of sodium metasilicate, sodium chloride and mixtures thereof and subsequently with a cationic collector, subjecting the conditioned mixture to froth flotation and separately recovering the froth product from the flotation operation, said froth product having a substantially higher potash spar content than said mixture of minerals.

2. The process of claim 1 wherein said sodium compound comprises sodium chloride.

3. The process of claim 1 wherein said sodium compound comprises sodium metasilicate.

4. The process of claim 1 wherein said cationic collector comprises an amine-type collector.

5. The process of claim 1 wherein said sodium compound is used in an amount within the range of from about 0.1 to about 50 pounds of sodium compound per ton of solids in said mixture.

6. The process of claim 1 wherein said sodium compound is used in an amount within the range of from about 0.5 to about 25 pounds of sodium compound per ton of solids in said mixture.

7. The process of claim 1 wherein said mixture of minerals comprises a feldspar flotation concentrate recovered in a prior flotation.

8. The process of claim 1 wherein the particles in said mixture are 4 mesh.

9. The process of claim 1 wherein substantially all of the particles in said mixture are of a size Within the range of from about 8 mesh 10 about 200 mesh.

10. The process of claim 1 wherein substantially all of the particles in said mixture are of a size within the range of from about 20 mesh to about 100 mesh.

References Cited in the file of this patent UNITED STATES PATENTS Ellis Aug. 8, Johnson Apr. 22, Johnson Apr. 23, OMeara Oct. 6, Snow Nov. 22, 

1. A PROCESS FOR SEPARATING POTASH SPAR FROM SODA SPAR WHICH COMPRISES CONDITIONING A SUBSTANTIALLY LIBERATED MIXTURE OF MINERALS CONTAINING POTASH SPAR AND SODA SPAR FIRST WITH A SODIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF SODIUM METASILICATE, SODIUM CHLORIDE AND MIXTURES THEREOF AND SUBSEQUENTLY WITH A CATIONIC COLLECTOR, SUBJECTING THE CONDITIONED MIXTURE TO FROTH FLOTATION AND SEPARATELY RECOVERING THE FROTH PRODUCT FROM THE FLOTATION OPERATION, SAID FROTH PRODUCT HAVING A SUBSTANTIALLY HIGHER POTASH SPAR CONTENT THAN SAID MIXTURE OF MINERALS. 